diff --git a/llvm/test/Transforms/InstCombine/to-ptrmask.ll b/llvm/test/Transforms/InstCombine/to-ptrmask.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/to-ptrmask.ll
@@ -0,0 +1,289 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 2
+; RUN: opt < %s -passes=instcombine -S | FileCheck %s
+
+declare ptr @llvm.ptrmask(ptr, i64)
+declare void @use.i64(i64)
+
+define ptr @GEP_default_pattern_to_ptrmask(ptr %p, i64 %m) {
+; CHECK-LABEL: define ptr @GEP_default_pattern_to_ptrmask
+; CHECK-SAME: (ptr [[P:%.*]], i64 [[M:%.*]]) {
+; CHECK-NEXT:    [[PI:%.*]] = ptrtoint ptr [[P]] to i64
+; CHECK-NEXT:    [[PI_M:%.*]] = and i64 [[PI]], [[M]]
+; CHECK-NEXT:    [[PI_OFF:%.*]] = sub i64 [[PI_M]], [[PI]]
+; CHECK-NEXT:    [[PM:%.*]] = getelementptr i8, ptr [[P]], i64 [[PI_OFF]]
+; CHECK-NEXT:    ret ptr [[PM]]
+;
+  %pi = ptrtoint ptr %p to i64
+  %pi_m = and i64 %pi, %m
+  %pi_off = sub i64 %pi_m, %pi
+  %pm = getelementptr i8, ptr %p, i64 %pi_off
+  ret ptr %pm
+}
+
+define <2 x ptr> @GEP_default_pattern_fail_vec(<2 x ptr> %p, <2 x i64> %m) {
+; CHECK-LABEL: define <2 x ptr> @GEP_default_pattern_fail_vec
+; CHECK-SAME: (<2 x ptr> [[P:%.*]], <2 x i64> [[M:%.*]]) {
+; CHECK-NEXT:    [[PI:%.*]] = ptrtoint <2 x ptr> [[P]] to <2 x i64>
+; CHECK-NEXT:    [[PI_M:%.*]] = and <2 x i64> [[PI]], [[M]]
+; CHECK-NEXT:    [[PI_OFF:%.*]] = sub <2 x i64> [[PI_M]], [[PI]]
+; CHECK-NEXT:    [[PM:%.*]] = getelementptr i8, <2 x ptr> [[P]], <2 x i64> [[PI_OFF]]
+; CHECK-NEXT:    ret <2 x ptr> [[PM]]
+;
+  %pi = ptrtoint <2 x ptr> %p to <2 x i64>
+  %pi_m = and <2 x i64> %pi, %m
+  %pi_off = sub <2 x i64> %pi_m, %pi
+  %pm = getelementptr i8, <2 x ptr> %p, <2 x i64> %pi_off
+  ret <2 x ptr> %pm
+}
+
+define ptr @GEP_default_pattern_with_multiuse_fail(ptr %p, i64 %m) {
+; CHECK-LABEL: define ptr @GEP_default_pattern_with_multiuse_fail
+; CHECK-SAME: (ptr [[P:%.*]], i64 [[M:%.*]]) {
+; CHECK-NEXT:    [[PI:%.*]] = ptrtoint ptr [[P]] to i64
+; CHECK-NEXT:    [[PI_M:%.*]] = and i64 [[PI]], [[M]]
+; CHECK-NEXT:    [[PI_OFF:%.*]] = sub i64 [[PI_M]], [[PI]]
+; CHECK-NEXT:    call void @use.i64(i64 [[PI_OFF]])
+; CHECK-NEXT:    [[PM:%.*]] = getelementptr i8, ptr [[P]], i64 [[PI_OFF]]
+; CHECK-NEXT:    ret ptr [[PM]]
+;
+  %pi = ptrtoint ptr %p to i64
+  %pi_m = and i64 %pi, %m
+  %pi_off = sub i64 %pi_m, %pi
+  call void @use.i64(i64 %pi_off)
+  %pm = getelementptr i8, ptr %p, i64 %pi_off
+  ret ptr %pm
+}
+
+define ptr @GEP_default_pattern_fail_i32(ptr %p, i32 %m) {
+; CHECK-LABEL: define ptr @GEP_default_pattern_fail_i32
+; CHECK-SAME: (ptr [[P:%.*]], i32 [[M:%.*]]) {
+; CHECK-NEXT:    [[TMP1:%.*]] = ptrtoint ptr [[P]] to i64
+; CHECK-NEXT:    [[PI:%.*]] = trunc i64 [[TMP1]] to i32
+; CHECK-NEXT:    [[PI_M:%.*]] = and i32 [[PI]], [[M]]
+; CHECK-NEXT:    [[PI_OFF:%.*]] = sub i32 [[PI_M]], [[PI]]
+; CHECK-NEXT:    [[TMP2:%.*]] = sext i32 [[PI_OFF]] to i64
+; CHECK-NEXT:    [[PM:%.*]] = getelementptr i8, ptr [[P]], i64 [[TMP2]]
+; CHECK-NEXT:    ret ptr [[PM]]
+;
+  %pi = ptrtoint ptr %p to i32
+  %pi_m = and i32 %pi, %m
+  %pi_off = sub i32 %pi_m, %pi
+  %pm = getelementptr i8, ptr %p, i32 %pi_off
+  ret ptr %pm
+}
+
+define ptr @GEP_default_pattern_fail_not_i8(ptr %p, i64 %m) {
+; CHECK-LABEL: define ptr @GEP_default_pattern_fail_not_i8
+; CHECK-SAME: (ptr [[P:%.*]], i64 [[M:%.*]]) {
+; CHECK-NEXT:    [[PI:%.*]] = ptrtoint ptr [[P]] to i64
+; CHECK-NEXT:    [[PI_M:%.*]] = and i64 [[PI]], [[M]]
+; CHECK-NEXT:    [[PI_OFF:%.*]] = sub i64 [[PI_M]], [[PI]]
+; CHECK-NEXT:    [[PM:%.*]] = getelementptr i16, ptr [[P]], i64 [[PI_OFF]]
+; CHECK-NEXT:    ret ptr [[PM]]
+;
+  %pi = ptrtoint ptr %p to i64
+  %pi_m = and i64 %pi, %m
+  %pi_off = sub i64 %pi_m, %pi
+  %pm = getelementptr i16, ptr %p, i64 %pi_off
+  ret ptr %pm
+}
+
+define ptr @builtin_align_up_to_ptrmask(ptr %x) {
+; CHECK-LABEL: define ptr @builtin_align_up_to_ptrmask
+; CHECK-SAME: (ptr [[X:%.*]]) {
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[INTPTR:%.*]] = ptrtoint ptr [[X]] to i64
+; CHECK-NEXT:    [[OVER_BOUNDARY:%.*]] = add i64 [[INTPTR]], 7
+; CHECK-NEXT:    [[ALIGNED_INTPTR:%.*]] = and i64 [[OVER_BOUNDARY]], -8
+; CHECK-NEXT:    [[DIFF:%.*]] = sub i64 [[ALIGNED_INTPTR]], [[INTPTR]]
+; CHECK-NEXT:    [[ALIGNED_RESULT:%.*]] = getelementptr inbounds i8, ptr [[X]], i64 [[DIFF]]
+; CHECK-NEXT:    ret ptr [[ALIGNED_RESULT]]
+;
+entry:
+  %intptr = ptrtoint ptr %x to i64
+  %over_boundary = add i64 %intptr, 7
+  %aligned_intptr = and i64 %over_boundary, -8
+  %diff = sub i64 %aligned_intptr, %intptr
+  %aligned_result = getelementptr inbounds i8, ptr %x, i64 %diff
+  ret ptr %aligned_result
+}
+
+define ptr @builtin_align_up_to_ptrmask_fail_invalid_constants1(ptr %x) {
+; CHECK-LABEL: define ptr @builtin_align_up_to_ptrmask_fail_invalid_constants1
+; CHECK-SAME: (ptr [[X:%.*]]) {
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[INTPTR:%.*]] = ptrtoint ptr [[X]] to i64
+; CHECK-NEXT:    [[OVER_BOUNDARY:%.*]] = add i64 [[INTPTR]], 7
+; CHECK-NEXT:    [[ALIGNED_INTPTR:%.*]] = and i64 [[OVER_BOUNDARY]], -16
+; CHECK-NEXT:    [[DIFF:%.*]] = sub i64 [[ALIGNED_INTPTR]], [[INTPTR]]
+; CHECK-NEXT:    [[ALIGNED_RESULT:%.*]] = getelementptr inbounds i8, ptr [[X]], i64 [[DIFF]]
+; CHECK-NEXT:    ret ptr [[ALIGNED_RESULT]]
+;
+entry:
+  %intptr = ptrtoint ptr %x to i64
+  %over_boundary = add i64 %intptr, 7
+  %aligned_intptr = and i64 %over_boundary, -16
+  %diff = sub i64 %aligned_intptr, %intptr
+  %aligned_result = getelementptr inbounds i8, ptr %x, i64 %diff
+  ret ptr %aligned_result
+}
+
+define ptr @builtin_align_up_to_ptrmask_fail_invalid_constants2(ptr %x) {
+; CHECK-LABEL: define ptr @builtin_align_up_to_ptrmask_fail_invalid_constants2
+; CHECK-SAME: (ptr [[X:%.*]]) {
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[INTPTR:%.*]] = ptrtoint ptr [[X]] to i64
+; CHECK-NEXT:    [[OVER_BOUNDARY:%.*]] = add i64 [[INTPTR]], 8
+; CHECK-NEXT:    [[ALIGNED_INTPTR:%.*]] = and i64 [[OVER_BOUNDARY]], -9
+; CHECK-NEXT:    [[DIFF:%.*]] = sub i64 [[ALIGNED_INTPTR]], [[INTPTR]]
+; CHECK-NEXT:    [[ALIGNED_RESULT:%.*]] = getelementptr inbounds i8, ptr [[X]], i64 [[DIFF]]
+; CHECK-NEXT:    ret ptr [[ALIGNED_RESULT]]
+;
+entry:
+  %intptr = ptrtoint ptr %x to i64
+  %over_boundary = add i64 %intptr, 8
+  %aligned_intptr = and i64 %over_boundary, -9
+  %diff = sub i64 %aligned_intptr, %intptr
+  %aligned_result = getelementptr inbounds i8, ptr %x, i64 %diff
+  ret ptr %aligned_result
+}
+
+define ptr @builtin_align_up_to_ptrmask_fail_multiuse(ptr %x) {
+; CHECK-LABEL: define ptr @builtin_align_up_to_ptrmask_fail_multiuse
+; CHECK-SAME: (ptr [[X:%.*]]) {
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[INTPTR:%.*]] = ptrtoint ptr [[X]] to i64
+; CHECK-NEXT:    [[OVER_BOUNDARY:%.*]] = add i64 [[INTPTR]], 7
+; CHECK-NEXT:    [[ALIGNED_INTPTR:%.*]] = and i64 [[OVER_BOUNDARY]], -8
+; CHECK-NEXT:    call void @use.i64(i64 [[ALIGNED_INTPTR]])
+; CHECK-NEXT:    [[DIFF:%.*]] = sub i64 [[ALIGNED_INTPTR]], [[INTPTR]]
+; CHECK-NEXT:    [[ALIGNED_RESULT:%.*]] = getelementptr inbounds i8, ptr [[X]], i64 [[DIFF]]
+; CHECK-NEXT:    ret ptr [[ALIGNED_RESULT]]
+;
+entry:
+  %intptr = ptrtoint ptr %x to i64
+  %over_boundary = add i64 %intptr, 7
+  %aligned_intptr = and i64 %over_boundary, -8
+  call void @use.i64(i64 %aligned_intptr)
+  %diff = sub i64 %aligned_intptr, %intptr
+  %aligned_result = getelementptr inbounds i8, ptr %x, i64 %diff
+  ret ptr %aligned_result
+}
+
+define ptr @builtin_align_down_to_ptrmask(ptr %x) {
+; CHECK-LABEL: define ptr @builtin_align_down_to_ptrmask
+; CHECK-SAME: (ptr [[X:%.*]]) {
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[INTPTR:%.*]] = ptrtoint ptr [[X]] to i64
+; CHECK-NEXT:    [[AND:%.*]] = and i64 [[INTPTR]], 7
+; CHECK-NEXT:    [[DIFF:%.*]] = sub nsw i64 0, [[AND]]
+; CHECK-NEXT:    [[ALIGNED_RESULT:%.*]] = getelementptr inbounds i8, ptr [[X]], i64 [[DIFF]]
+; CHECK-NEXT:    ret ptr [[ALIGNED_RESULT]]
+;
+entry:
+  %intptr = ptrtoint ptr %x to i64
+  %and = and i64 %intptr, 7
+  %diff = sub nsw i64 0, %and
+  %aligned_result = getelementptr inbounds i8, ptr %x, i64 %diff
+  ret ptr %aligned_result
+}
+
+define ptr @builtin_align_down_to_ptrmask_fail_non_mask(ptr %x) {
+; CHECK-LABEL: define ptr @builtin_align_down_to_ptrmask_fail_non_mask
+; CHECK-SAME: (ptr [[X:%.*]]) {
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[INTPTR:%.*]] = ptrtoint ptr [[X]] to i64
+; CHECK-NEXT:    [[AND:%.*]] = and i64 [[INTPTR]], 8
+; CHECK-NEXT:    [[DIFF:%.*]] = sub nsw i64 0, [[AND]]
+; CHECK-NEXT:    [[ALIGNED_RESULT:%.*]] = getelementptr inbounds i8, ptr [[X]], i64 [[DIFF]]
+; CHECK-NEXT:    ret ptr [[ALIGNED_RESULT]]
+;
+entry:
+  %intptr = ptrtoint ptr %x to i64
+  %and = and i64 %intptr, 8
+  %diff = sub nsw i64 0, %and
+  %aligned_result = getelementptr inbounds i8, ptr %x, i64 %diff
+  ret ptr %aligned_result
+}
+
+define ptr @builtin_align_down_to_ptrmask_fail_not_i8(ptr %x) {
+; CHECK-LABEL: define ptr @builtin_align_down_to_ptrmask_fail_not_i8
+; CHECK-SAME: (ptr [[X:%.*]]) {
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[INTPTR:%.*]] = ptrtoint ptr [[X]] to i64
+; CHECK-NEXT:    [[AND:%.*]] = and i64 [[INTPTR]], 7
+; CHECK-NEXT:    [[DIFF:%.*]] = sub nsw i64 0, [[AND]]
+; CHECK-NEXT:    [[ALIGNED_RESULT:%.*]] = getelementptr inbounds <2 x i8>, ptr [[X]], i64 [[DIFF]]
+; CHECK-NEXT:    ret ptr [[ALIGNED_RESULT]]
+;
+entry:
+  %intptr = ptrtoint ptr %x to i64
+  %and = and i64 %intptr, 7
+  %diff = sub nsw i64 0, %and
+  %aligned_result = getelementptr inbounds <2 x i8>, ptr %x, i64 %diff
+  ret ptr %aligned_result
+}
+
+define ptr @builtin_align_down_to_ptrmask_fail_i32(ptr %x) {
+; CHECK-LABEL: define ptr @builtin_align_down_to_ptrmask_fail_i32
+; CHECK-SAME: (ptr [[X:%.*]]) {
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[TMP0:%.*]] = ptrtoint ptr [[X]] to i64
+; CHECK-NEXT:    [[INTPTR:%.*]] = trunc i64 [[TMP0]] to i32
+; CHECK-NEXT:    [[AND:%.*]] = and i32 [[INTPTR]], 7
+; CHECK-NEXT:    [[DIFF:%.*]] = sub nsw i32 0, [[AND]]
+; CHECK-NEXT:    [[TMP1:%.*]] = sext i32 [[DIFF]] to i64
+; CHECK-NEXT:    [[ALIGNED_RESULT:%.*]] = getelementptr inbounds i8, ptr [[X]], i64 [[TMP1]]
+; CHECK-NEXT:    ret ptr [[ALIGNED_RESULT]]
+;
+entry:
+  %intptr = ptrtoint ptr %x to i32
+  %and = and i32 %intptr, 7
+  %diff = sub nsw i32 0, %and
+  %aligned_result = getelementptr inbounds i8, ptr %x, i32 %diff
+  ret ptr %aligned_result
+}
+; We could match this pattern without ever including extra instructions
+define ptr @builtin_align_down_up_ptrmask_non_const_TODO(ptr %x, i64 %alignment) {
+; CHECK-LABEL: define ptr @builtin_align_down_up_ptrmask_non_const_TODO
+; CHECK-SAME: (ptr [[X:%.*]], i64 [[ALIGNMENT:%.*]]) {
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[MASK:%.*]] = add i64 [[ALIGNMENT]], -1
+; CHECK-NEXT:    [[INTPTR:%.*]] = ptrtoint ptr [[X]] to i64
+; CHECK-NEXT:    [[OVER_BOUNDARY:%.*]] = add i64 [[MASK]], [[INTPTR]]
+; CHECK-NEXT:    [[INVERTED_MASK:%.*]] = sub i64 0, [[ALIGNMENT]]
+; CHECK-NEXT:    [[ALIGNED_INTPTR:%.*]] = and i64 [[OVER_BOUNDARY]], [[INVERTED_MASK]]
+; CHECK-NEXT:    [[DIFF:%.*]] = sub i64 [[ALIGNED_INTPTR]], [[INTPTR]]
+; CHECK-NEXT:    [[ALIGNED_RESULT:%.*]] = getelementptr inbounds i8, ptr [[X]], i64 [[DIFF]]
+; CHECK-NEXT:    ret ptr [[ALIGNED_RESULT]]
+;
+entry:
+  %mask = add i64 %alignment, -1
+  %intptr = ptrtoint ptr %x to i64
+  %over_boundary = add i64 %mask, %intptr
+  %inverted_mask = sub i64 0, %alignment
+  %aligned_intptr = and i64 %over_boundary, %inverted_mask
+  %diff = sub i64 %aligned_intptr, %intptr
+  %aligned_result = getelementptr inbounds i8, ptr %x, i64 %diff
+  ret ptr %aligned_result
+}
+; We would need to create an extra NOT instruction here
+define ptr @builtin_align_down_to_ptrmask_non_const_fail(ptr %x, i64 %alignment) {
+; CHECK-LABEL: define ptr @builtin_align_down_to_ptrmask_non_const_fail
+; CHECK-SAME: (ptr [[X:%.*]], i64 [[ALIGNMENT:%.*]]) {
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[INTPTR:%.*]] = ptrtoint ptr [[X]] to i64
+; CHECK-NEXT:    [[ADD:%.*]] = add i64 [[ALIGNMENT]], -1
+; CHECK-NEXT:    [[AND:%.*]] = and i64 [[ADD]], [[INTPTR]]
+; CHECK-NEXT:    [[DIFF:%.*]] = sub i64 0, [[AND]]
+; CHECK-NEXT:    [[ALIGNED_RESULT:%.*]] = getelementptr inbounds i8, ptr [[X]], i64 [[DIFF]]
+; CHECK-NEXT:    ret ptr [[ALIGNED_RESULT]]
+;
+entry:
+  %intptr = ptrtoint ptr %x to i64
+  %add = add i64 %alignment, -1
+  %and = and i64 %add, %intptr
+  %diff = sub i64 0, %and
+  %aligned_result = getelementptr inbounds i8, ptr %x, i64 %diff
+  ret ptr %aligned_result
+}